Synthesis of syringolide 1 ketals and esters for receptor studies

Article abstract of DOI:10.1016/S0031-9422(96)00530-4

The syringolides, specified by avirulence gene D from Pseudomonas syringae, elicit a disease defense reaction only in soybean cultivars carrying the Rpg4 disease resistance gene. In order to identify structural features important for elicitor activity and construct highly labelled elicitor-active probes, several syringolide esters and ketals were synthesized. Alteration of the C-3 hemiketal group of syringolide 1 abolished elicitor activity, but ester derivatives based on the C-4' hydroxy group all retained activity. [¹²⁵I]4'-(2-iodo-3,4,5-trimethoxyphenylacetyl) syringolide 1 was prepared for receptor studies.